I just saw someone post this in another thread and might be exactly what I’ve been looking for to bypass my 433RF ceiling fan controls. 
https://www.itead.cc/sonoff-ifan02-wifi-smart-ceiling-fan-with-light.html
Does anyone have any experience with these? can you flash a custom firmware on them and maintain the functioning of the included remote control?
Nice. I have implemented my own solution to get the state of my fans (6 speed and a light). I use the sonoff pow to gather info on what speed the fan is running based on power consumption (in case someone uses the physical remote for example).
To control the fans via ha, I use Pilight to send the raw commands.
Unfortunately my fans have the controller built in, so it would take quite some work.
Btw the Sonoff pow is not very reliable reporting low power consumptions (fan pulls 50w at full speed and light on), lots of ups and down even with the fan off.
I am probably going to change them for xiaomi zigbee plugs using zigbee2mqtt to get maybe more steady and frequent reports of power consumption.
being only $13 it might be worth it to be the guinea pig on this and see how it goes. If no one else tries it first…(hint, hint, wink, wink).
Honestly I don’t know if I’m smart enough to figure it out. 
I don’t see it listed on the Tasmota GitHub page but probably worth a go. Lots of other Sonoff devices are flashable.
It’s there now. Looks like just in the last couple of days. I’m going to go ahead and order a few. My fans rely entirely on an external controller so this should be pretty straight forward for my setup. But apparently you need to connect it to mains to flash it as usb doesn’t deliver enough power, so that could be a bit concerning.
Or use a larger current power supply instead of mains.
My xiaomi zigbee power plug (via xiaomi gateway hub) has a significant delay before updating the watts used in HA. However via the app it updates faster.
Btw. This fan nnow has tasmota firmware available so you can control via mqtt.